The objective of this work is the structural analysis of follicle-stimulating hormone (FSH) from the porcine and human species, and of human luteinizing hormone. No chemical characterization of porcine FSH has yet been reported. Following purification of the hormone, amino acid sequence analysis of the separate subunits will be carried out. Physical-chemical properties and conformational characteristics will be assessed, as well as comparative biological and immunological activity. While amino acid sequences of the two human hormones have been reported by other laboratories, a number of discrepancies are evident among the published structures which await independent confirmation. Our sequence analysis of the alpha and beta subunits of human luteinizing hormone is now almost complete. Human FSH subunits are being prepared for similar structural study with particular emphasis on the beta subunit where the major discrepancies are found. Using the peptide fragments obtained during structural analysis of these hormones, region-specific antisera will be obtained, both by characterization of existing antisera and by direct animal immunization. These will be used in neutralization experiments aimed at defining the structural requirements for biological and immunological activity, as well as in probing for fragments or altered metabolic forms of hormone in the circulation.